As you can tell, I’ve been on a bit of an energy kick recently. It seems there is so much being said about the subject these days, but quietly some are taking hold of the technology for themselves. Governments will continue to bicker about the science, usefulness and economic sense, but the truth is we all make our own decisions when it comes to spending, including the government. Some of the largest budget items in most annual governmental budgets are what I would consider an absolute waste of taxpayer money. I guess it’s a matter of priorities.
Just a few weeks ago, I was traveling in Canada with my wife to visit family. Along the way, we kept encountering solar units similar to this one that I photographed in Southwestern Ontario. According to the Siemens Corporation, panels equipped with a moveable mounting and a new control system are able to precisely follow the course of the sun. Thanks to a new algorithm based on astronomical data, the solar panels track the sun in line with not only the time of day but also the time of year and the precise geographical location of the photovoltaic installation. As a result, their energy yield is more than 35 percent higher than fixed systems. This is much higher than some earlier units which yielded an increase of only 15%.
A decisive factor in the efficiency of a photovoltaic system is the angle of incidence at which sunlight strikes the surface of the module. In the case of fixed panels, sunlight hits the solar cells at an oblique angle for most of the day. A maximum yield in terms of energy and therefore electricity is only achieved when sunlight strikes the cells perpendicular to their surface. So the obvious solution is to fit the solar modules to a movable tracking system that precisely follows the course of the sun. The sun’s position depends on not only the time of day but also the time of year and the location of the photovoltaic installation. Some systems even calculate the perfect alignment for the solar modules on the basis of their precise location, anywhere in the world, and the exact time and date.
This calculation is based on what they call the “Simatic Library for Solar Position Algorithm,” which is stored in every control unit. Siemens obtained a license for the very precise algorithm from the National Renewable Energy Laboratory (NREL) in the U.S. On this basis, the control system is able to determine the position of the sun to an accuracy of 0.0003° and align the photovoltaic module accordingly. Three-phase AC motors power a dual-axis tracking system: This swivels the module in a semicircle along what is known as the azimuthal axis, thus tracking the sun’s daily course from east to west, and tilts the module along the zenithal axis, tracking the height of the sun according to the time of day and year. In the process, the control system also prevents neighboring modules from overshadowing one another during the morning and evening hours, when shadows are especially long. The software bases its astronomical calculations on parameters such as longitude, latitude, and the exact time.
In addition, the control system can also take weather conditions into account (a common complaint among critics of such systems). When faced with high winds, for example, it moves the modules to a position of least resistance, where they can withstand winds of up to 130 kilometers per hour. In a similar manner, the tracking system can be programmed to react to snow, thunderstorms, fog, and darkness.
In most cases, owners are able to not only supply their own energy needs, but can also contribute to the local electrical grid and in doing so, receive a check from the utilities company on a monthly basis. However, one should not expect to be paying for the cost of one of these units too soon. And I suppose that’s where the criticism begins.
According to a number of sources, including Green Building Advisors, the cost of photovoltaic systems are actually dropping dramatically. In April 2010, a photovoltaic system cost $8 a watt. Here are the numbers. A one-kilowatt PV system (about 4 – 5 solar modules in the Midwest) generates about 1,300 kWH per year. If you bought 1,300 kWH of electricity from our local utility (burning natural gas, fuel oil, hydro and coal), they would charge you $0.16 / kWH, or $208 / year.
If you’re conservative with expectations, a PV array (fixed in this case) you would last you 25 years, and make you $5,200 of electricity over its working lifetime, assuming electricity prices never increase. No one believes costs will stay where they are, but it makes the math easier, and we’re being conservative?
So there’s the issue: you pay $8,000 for a system that only makes you $5,200 of electricity over its lifetime, not including tax credits and inflation assumptions and lots of other complicated financial math to make those panels “worth it” to may people.
However, in 2011 prices people were getting for PV were $4,500 per kW before tax credits. It dropped 45% since 2011. So now a system that makes us $5,200 of electricity cost $4,500.
Still not convinced of the potential value. Well than perhaps it is a matter of priorities and what each individual values most. I often read people complaining about the high cost of solar units, the potential for premature obsolescence and the uncertainty of realizing a substantial profit. But let me ask you this: for the person who invests in a motor home, what kind of return do they get on their investment of $200,000 – $300,000? What about the cinema viewing room in the basement, or the motorboat for the lake? No one expects a financial return on any of these items, yet they hand over their money without thought (well, at least some do).
My point is this, people spend there money where they want to. They choose to spend according to their values. Some people value clean energy and self-sufficiency. So they may lose a couple of thousand dollars over 25 years. Tell me how much a 25 year old motorhome is worth and what it did to protect the planet.
